共查询到19条相似文献,搜索用时 171 毫秒
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通过改变化学镀液中金属离子Co2+与(Co2++Ni2+)的摩尔浓度比获得了不同的Ni-Co-P合金化学镀层。研究了钴的引入对Ni-Co-P合金镀层的沉积速率及组织性能的影响。结果表明:随着Co2+与(Co2++Ni2+)摩尔浓度比的增加,镀层的沉积速率不断下降,镀层中P含量逐渐减小,镀层表面的胞状组织由大到小;镀层硬度随Co2+与(Co2++Ni2+)摩尔浓度比的增加先升高后降低,Co2+与(Co2++Ni2+)摩尔浓度比为0.4时,硬度最大达554.12HV,镀层具有优良的耐硫酸腐蚀性能,Co2+与(Co2++Ni2+)摩尔浓度比为0.6时,镀层耐蚀性最强。 相似文献
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为了改善化学镀Ni-Co-P合金工艺存在的镀速慢、镀层质量差等问题,研究了镀液组分、表面活性剂、pH值、稳定剂、配位剂对化学镀Ni-Co-P合金镀层沉积速度、耐蚀性、孔蚀率的影响,得出最佳镀液配方和工艺:26 g/L CoSO4,28 g/L NiSO4,22 g/L NaH2PO2,80 g/L Na3C6H5O7,69 g/L(NH4)2SO4,1 mg/L KI,50 mg/L十二烷基苯磺酸钠,pH=8,温度85℃.本研究结果为化学镀Ni-Co-P合金工艺提供了依据,较有实用价值. 相似文献
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对烧结NdFeB磁体作Al-Mn合金镀可以提高其耐腐蚀性能,但这只能在无水体系中进行.以MnCl2-AlCl3-BMIC(氯化1-丁基-3-甲基咪唑)为离子液体(AlCl3与BMIC的摩尔比为2∶1),对NdFeB磁体电沉积Al-Mn合金.采用SEM扫描电镜观察了Al-Mn镀层的形貌,采用X射线衍射分析了相结构,采用3.5%NaCl溶液测试了耐腐蚀性能;探讨了离子液体中MnCl2浓度对Al-Mn合金镀层结构及性能的影响.结果表明:NdFeB磁体表面电沉积Al-Mn合金,当离子液体中MnCl2浓度为0.05~0.25 mol/L时,Al-Mn合金镀层的结构由晶态逐渐转变为非晶态,耐腐蚀性能显著提高,且优于铝镀层. 相似文献
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化学沉积Ni-Mo-P合金工艺参数对性能的影响 总被引:3,自引:0,他引:3
研究了镀液pH值和温度等工艺参数对化学镀Ni Mo P合金镀层耐蚀性和硬度的影响。试验结果表明 ,镀液 pH值升高 ,镀层的沉积速度和硬度升高 ,而耐蚀性下降 ;镀液温度升高 ,镀层的沉积速度升高 相似文献
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《材料保护》2020,(1)
为了提高镁合金耐腐蚀性能,在AZ61镁合金表面制备Ni-P化学镀层。采用磷酸酸洗对镁合金表面前处理后,在酸性镀液中制备了Ni-P化学镀层,通过SEM、EDAX、XRD及动电位极化曲线、交流阻抗等方法,分析了镀液p H值对Ni-P镀层形貌、成分、厚度、结合力、结构和耐蚀性的影响。试验结果表明:随着镀液p H值升高,组成镀层的细胞状物尺寸逐渐减小,镀层的沉积速度加快,镀层中的磷含量逐渐降低,镀层中的镍含量逐渐上升,镀层的晶化程度逐渐提高。镀层的耐蚀性能则随着镀液pH值的上升先升高,后下降。p H=6.0条件下制备的Ni-P镀层在质量分数为3.5%NaCl溶液中的交流阻抗膜值最高,且自腐蚀电流密度最低,耐蚀性能最好,并根据试验结果分析了镀液pH值对Ni-P镀层耐蚀性能的影响机制。 相似文献
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Various electroless Ni-Co-P films were deposited on silicon substrates in electroless baths using sodium hypophosphite as reducing agent and nickel and cobalt sulfates as ion source at pH value of 9 and temperature from 55 to 85 °C. The effect of the atomic ratio of Co to Ni + Co in baths on the growth behavior of the electroless Ni-Co-P films was studied. The various electroless Ni-Co-P films were characterized by scanning electron microscopy for the morphology, transmission electron microscopy for the microstructure and thickness, and energy dispersion spectroscopy for the composition. The results showed that the growth rate of the electroless Ni-Co-P films is generally increased with increase of the bath temperature and is decreased with atomic ratio of Co to Ni + Co in baths. The reduction of the Co2+ ion is easier than the Ni2+ ion in various baths, except for the bath with 0.9 atomic ratio of Co to Co + Ni. 相似文献
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Senlin WANGCollege of Materials Science Engineering Huaqiao University Quanzhou ChinaAssoc. Prof. Ph.D. 《材料科学技术学报》2005,21(1):39-42
Electroless Ni-Fe-P alloys in an alkaline bath were plated. The effects of deposition parameters on the plating rate and the coating composition were examined. The weight loss test and the anodic polarization measurement of the deposits in 3.5 wt pct NaCI solution (pH7.0) showed that the deposits with the mole ratio of NiS04/FeSO4 being 0.07:0.03, pH8.0 and 7.5 possess better corrosion resistance than that of the other deposits and the Ni-Fe-P deposits did not form passive films in this environment. In 5.0 wt pct NaOH solution, the Ni-Fe-P deposits have better corrosion resistance and formed passive films. 相似文献
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Electroless nickel (EN) plating has received attention as a hard coating for industrial applications due to its high hardness,
uniform thickness as well as excellent corrosion and wear resistance. The electroless Ni–P deposit is a supersaturated alloy
in as-deposited state, and can be strengthened by precipitation of nickel phosphide crystallites with suitable heat treatments.
However, the hardness of Ni–P films degrades with excessive annealing due to grain coarsening. This is the most severe barrier
for electroless Ni–P deposition process from replacing chromium plating in industrial sectors. This problem is addressed in
the paper by modifying the conventional electroless Ni–P bath to co-deposit tungsten to increase the hardness of the coating.
Structural changes in the coating due to incorporation of tungsten are also highlighted. Deposition is done from an alkaline
hypophosphite bath. Deposits with varying tungsten content are synthesized. Chemical analysis shows that tungsten incorporation
reduces the phosphorus content in the deposit. Phosphorus content varied from 3 to 7 wt.% depending upon the tungsten incorporation
in the deposit which in turn varied between 8 and 18 wt.%. Coatings with high tungsten content possess high hardness when
compared to binary Ni–P as well as low tungsten ternary alloy deposits. 相似文献
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Molybdenum black solar selective coatings have been produced on cobalt by immersion in a solution of ammonium paramolybdate
and nickel sulphate. The cobalt was electroplated on nickel-plated copper prior to immersion in the paramolybdate solution.
The maximum solar absorptance of the resulting molybdenum black coating was about 0.91. The minimum emittance was about 0.1
for coatings on cobalt deposited with an addition agent and about 0.23 for coatings on cobalt deposited without addition agent
in the 60 °C plating solution. These differences have been related to the coating morphology determined by scanning electron
microscopy. The emittance of coatings on cobalt deposited without addition agent decreases (or remains unchanged) during short-term
heat treatment while that of coatings deposited on cobalt plated with addition agent increases somewhat. Reduction of the
cobalt plating bath temperature to 45 °C can also lead to good initial coating properties but without the requirement for
an addition agent in the cobalt plating bath. XPS studies show that the oxidation state of molybdenum in the coatings is approximately
+ 5 corresponding to Mo4O11. This reduces to + 4 after argon ion bombardment. Some cobalt may be present in the coatings in the form of CoO. 相似文献